“None Disclosure Agreements, where you’re not allowed to talk about anything. I have something coming out where there’s an amount of money where if it leaks because of me, I don’t get that payment. If I keep it a secret until the day it comes out, I get that payment. I’m good about keeping secrets.

“I’m proud of the fact that I knew a year and a half before anybody else that he was actually Dad Vader. I didn’t tell Harrison, or my wife because I thought it would be terrible if she said ‘You know what…’ to a fan and it got out. Irvin Kershner (director of The Empire Strike Back) said ‘I know something, I’m going to tell you. George knows, I know, and now I’m going to tell you and if it leaks we’ll know it’s you.’ Because the line originally was ‘You don’t know the truth, Obi Wan killed your father,’ and he said we’re going to take out that line and put it in ‘I am your father.’

“I thought well first of all if Sir Alec Guinness is the real villain that’s a pretty good twist in and of itself, but this is even better. Couldn’t believe it, I was so excited. Just a mind-boggling plot twist. I still remember when we saw the first screening, Harrison turned to me and said ‘You never told me that.’ I said ‘I know, but I would have gotten in trouble if I told you.’

“Now it’s happening all over again, I’m not even authorised to tell you I’m in Episode VII. It’s all secret.”